Two submarines, the Rostov-on-Don B-237 and the Stary Oskol B-262, practised emergency deployments for detecting, accompanying and destroying sea and coastal targets with rocket fire, the Defence Ministry said.

Submarine crews from the Black sea fleet were also due to practice deep dives and to work on techniques such as emergency surfacing, it said.

The statement did not give a start or end date for the drills or say if the submarine exercises were part of larger-scale drills in the Black Sea and on the Crimean peninsula annexed by Russia in 2014.

A navigation warning to shipping published by Turkey’s navy said that “firing exercises” were expected in the region from December 3 to 9.

It comes as a startling study by the The Human Security Centre concluded Russia would be able to may be able to "overrun vulnerable areas of NATO territory" in a matter of hours

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NATO foreign ministers discussed the Black Sea region with Ukraine and Georgia’s foreign ministers yesterday while NATO Secretary General Jens Stoltenberg said the US-led military alliance had boosted its presence there in response to what he said were Russia’s aggressive actions.

The report was written by HSC, which is an independent international affairs organisation that has an interest in foreign, defence and security policy.

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